Methods of preparing a composite having elastomer and filler

Abstract

Disclosed herein are methods of preparing composites from solid elastomer(s) and wet filler(s), as well as products, including composites, vulcanizates, and articles therefrom. The wet filler can have a liquid content of at least 15%. A resulting composite comprises the filler dispersed in the elastomer at a loading of at least 20 phr with a filler yield loss of no more than 10%, wherein the composite has a liquid content of no more than 10% by weight based on total weight of said composite.

The invention claimed is: 
     
       1. A composite comprising a filler dispersed in an elastomer, wherein the filler comprises carbon black in an amount of at least 50% by weight relative to the total weight of the filler and the elastomer comprises at least 50% by weight of natural rubber relative to the total weight of the elastomer, and the composite has the following properties:
 (a) the filler has a state of dispersion in the elastomer according to equation (1):
     A≤ 1.25* B+x   (1)
 
 
 wherein: 
 A is d 90  of the area-equivalent diameter (μm) of filler particles in the composite, and 
 
       
         
           
             
               B 
               ⁢ 
               
                   
                    
               
               ⁢ 
               is 
               ⁢ 
                   
               
                 
                   
                     
                       
                         [ 
                         
                           
                             total 
                             ⁢ 
                                 
                             area 
                             ⁢ 
                                 
                             of 
                             ⁢ 
                                 
                             particles 
                             ⁢ 
                                 
                             having 
                             ⁢ 
                                 
                             an 
                             ⁢ 
                                 
                             area 
                           
                           - 
                         
                       
                     
                   
                   
                     
                       
                         
                           
                             equivalent 
                             ⁢ 
                                 
                             diameter 
                             ⁢ 
                                 
                             of 
                           
                           ≥ 
                           
                             2 
                             ⁢ 
                                 
                             
                               µ 
                               ⁢ 
                               m 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   [ 
                   
                     total 
                     ⁢ 
                         
                     imaging 
                     ⁢ 
                         
                     area 
                   
                   ] 
                 
               
               × 
               100 
               ⁢ 
               % 
             
           
         
         
           wherein B≥1%, 
         
         A and B are determined by optical microscopy in transmission mode of microtomed sections, and 
         x is a number ranging from 15 to 20; and 
         (b) the composite has a property according to equation (2):
     G ′(0.1%)/ G ′(200%)≤0.1* G ′(50%)− y   (2)
 
 
         wherein G′(0.1%) is a dynamic storage modulus measured at 0.1% strain amplitude, G′(200%) is a dynamic storage modulus measured at 200% strain amplitude, G′(50%) is a dynamic storage modulus measured at 50% strain amplitude, the dynamic storage modulus is measured at 100° C. at a frequency of 1 Hz, and y is a number ranging from 7 to 10. 
       
     
     
       2. The composite of  claim 1 , wherein the elastomer further comprises at least one rubber selected from polybutadiene rubber and styrene-butadiene rubber. 
     
     
       3. The composite of  claim 1 , wherein x=15. 
     
     
       4. The composite of  claim 1 , wherein y=10. 
     
     
       5. The composite of  claim 1 , wherein the carbon black has an STSA of at least 60 m 2 /g. 
     
     
       6. The composite of  claim 1 , wherein the carbon black has a COAN of at least 75 mL/100 g. 
     
     
       7. The composite of  claim 1 , wherein the carbon black has a ratio of BET/STSA ranging from 1 to 1.2. 
     
     
       8. The composite of  claim 1 , wherein the composite has a carbon black loading of 60 phr or less. 
     
     
       9. The composite of  claim 1 , wherein the filler further comprises silica.